<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div class="box">
    <ul>
      <li v-for="(item,index) in list">{{item}} &nbsp <button @click="del(index)">删除</button> </li>
    </ul>
    <button @click="fn">按钮</button>
  </div>

  <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
  <script>

    const app = new Vue({
      el: '.box',
      data: {
        list: []
      },
      methods: {
        fn() {
          const num = Math.ceil(Math.random() * 20)
          this.list.push(num)
        },
        del(id) {
          this.list.splice(id, 1)
        }
      }
    })
  </script>
</body>

</html>